When Worlds Collide
by Nintendoman01
Summary: A dark entity has designs on the worlds of Mario, Sonic, and Mega Man. Worlds collide in what is quite possibly the greatest adventure of their lives.
1. Prologue: A Dark Scheme

_**Mario, Sonic, & Mega Man: Heroes United**_

_**By Nintendoman01**_

* * *

**Disclaimer:**

I do not own Mario, Sonic, Mega Man, or any associated characters. They are the property of Nintendo, Sega, and Capcom, respectively. All rights reserved.

**Author's Note: **

I know what you're thinking: "Why the heck are you not working on your other stories?" What can I say: when I get the urge to write a story about something, I just can't help it. This was inspired by, among other things, Azurixx's story _Mario and Sonic: Heroes Unite!_ and Archie Comics' _Sonic and Mega Man: Worlds Collide_.

In terms of chronology, I've decided to set this fic after the events of _Super Mario 3D World_, _Sonic Lost World,_ and _Mega Man 10_. I've also mixed and matched different characters and concepts from the different Mario, Sonic, and Mega Man TV series and comics; you'll see what I mean as I go on.

* * *

**-Prologue- **

**A Dark Scheme**

* * *

**Vanda**

A mysterious being stood at the balcony of his large castle, overlooking his homeworld of Vanda. As far as the eye could see, the world was a large expanse of crystal and crystalline matter in various shapes and sizes, with a black starry sky overlooking said terrain.

The entity in question was a tall, powerfully built humanoid being, covered head-to-toe in a black-and-silver cloak topped with a hood, leaving nothing of his body visible except a pair of glowing red eyes. He was the Dark Mage, ruler of Vanda. However, it was not enough to simply rule Vanda; he needed more, and had found three suitable dimensions to spread his influence.

At that moment, he heard a door open behind him, and turned to face the one who entered.

What faced him was a large, muscular being, with purple skin and red scar-like markings snaking around his arms and one extending from his right eyebrow down his bare chest. He also had red eyes, purple hair just a shade darker than his skin, two golden-feathered wings, and two long bull-like horns, the left one seemingly turned upside down. His waist was covered with a mass of crystals, and instead of legs, he had a long, purple, snakelike tail. He bowed respectfully to the Dark Mage.

"What do you request of me, my Master?" the newcomer asked, his voice booming. The Dark Mage nodded at him.

"At ease, Culex," he said, his voice a deep baritone. "I have found three new worlds that would work marvelously for our new territory."

Beckoning for Culex to join him on the balcony, the Mage turned and waved his hand, three dimensional "windows" materializing before them. He gestured to the window on the right, depicting a small town filled with short people with mushroom-like heads.

"You recall that I sent you to here, to the Mushroom World a few years back," he said, then gestured to the window in the center, depicting a lush green landscape filled with anthropomorphic animals of all sizes, shapes, and colors.

"This world is called Mobius," he continued. "And this one..." he said before gesturing to the final window, depicting a large, bustling city filled with humans and, oddly enough, robots, "is the planet Earth in the year 20XX. These three worlds will be our next conquests."

"But sire," Culex said, somewhat baffled, "you know that the Mushroom World is uninhabitable for our kind. If we go there, we will die."

"I have found ways around this, Culex," the Mage said patiently. "I have already found others to take over in our name. They may think they will conquer for themselves, but it is _we_ who will be pulling the strings."

With that, he snapped his fingers, and the windows changed to depict three different people. Culex eyed each one of them closely, memorizing every detail.

The leftmost window showed an image of a big burly creature that resembled a cross between a dragon and a turtle. His hair was a fiery red-orange, as were the eyebrows that topped a pair of red eyes. His face was green, as was the shell on his back that was covered with sharp spikes, while his muzzle and underbelly were flesh-colored, the former filled with sharp teeth. His arms, legs, and tail were an orange-tinged yellow, while he wore several black spiked collars around his arms and neck. His eight fingers, as well as his six toes, were tipped with razor-sharp claws.

The middle window depicted a tall, portly, bald human man with a large pink nose and bushy brown mustache, complete with a pair of dark pince-nez sunglasses and a pair of goggles on his head. He wore a red-and-white uniform-like shirt with golden clasps and white gloves over a pair of black pants and boots.

The final window showed another human man, this one elderly and bald except for a ring of gray hair around his head shaped like devil horns, with a matching gray mustache. He wore a white lab coat over a white long-sleeved dress shirt and red tie, with blue jeans and brown work boots.

"You see before you King Bowser of the Koopa Troop, Doctor Ivo Robotnik, or Doctor Eggman as most know him, and Doctor Albert W. Wily," the Dark Mage said, gesturing to each window in turn. "They have failed to conquer their own respective worlds before, but together, they will be victorious."

"And how exactly are they going to meet to do this, my Lord?" Culex asked. Under his cloak, the Mage grinned.

"That, my good servant, is where we come in."

* * *

**Author's Note:  
**

And here's the prologue. Some of you may recognize Culex as the secret boss from _Super Mario RPG: Legend of the Seven Stars._

The board has been set. What's gonna happen now? Tune in next time to find out!

Please R&R.


	2. The Stage is Set

**- Chapter 1 -**

**The Stage is Set **

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**Bowser's Castle, Dark Land, The Mushroom World **

"_GRAAAAHHH!_"

Bowser rammed his fist into the wall, punching a large hole in it. He furiously stomped around his bedroom in a rage. It had been a few hours since he had returned from the Sprixie Kingdom after Mario and his friends saved the seven princesses and thwarted his plans there, and he was naturally furious that Mario had stopped him again.

"That stupid _Mario_!" he snarled, saying Mario's name with a tone of complete anger and disgust. "Every time! Every single time I get my plans underway, that stinking plumber shows up and ruins everything! He makes me so mad, I just wanna-"

In a blind rage, Bowser unleashed his fiery breath, the flaming torrent scorching the curtains on his window. He stood there, breathing heavily while trying to rein in his temper.

"You certainly seem to be in a bad mood."

Startled, Bowser whirled around to come face-to-face with a purple being around his size. His eyes widened in recognition.

"Wait, I know you," he said. "You're that Culex guy that I took down with Mario a few years back." Culex nodded.

"Indeed I am, King Bowser," he replied, folding his arms across his chest. "I, too, wish to have revenge on Mario. I have come to give you aid."

"But didn't you say that you couldn't survive in our universe for long?" Bowser asked curiously.

"This is true," Culex confirmed. "However, I didn't say that I myself would be directly aiding you."

Culex pointed his finger at the wall near the window, which suddenly morphed into a glowing white door-shaped portal.

"This portal will take you to a pocket dimension where you will meet two men similar to you, one of whom you may recognize," he explained. "Like you, they have faced many hardships from their arch-rivals, many plans and dreams foiled. Individually, you have failed, but together, you _will_ be victorious."

Bowser thought it over for a minute, and then grinned wickedly.

"Okay, I'm in," he said. "Let's do this."

With that, Bowser made his way into the portal.

* * *

**Death Egg Mark 2, Mobius  
**

None of Eggman's various subordinates said a word as he stomped onto the docking bay of the Death Egg Mark 2. Judging by his sour disposition, as well as the missing left half of his mustache, they knew it was in their best interest and health not to bother him for now. They did deduce, however, that his operations on the Lost Hex had been effectively halted.

Behind him was Orbot, with Cubot's head still attached to his body. Again, no one commented on it. However, when they reached the control room, one person in particular could not help but start snickering at the sight of Eggman's tattered mustache: Dr. Eggman's right-hand man/nephew, Snively Robotnik.

Snively was a short, skinny man, bald except for numerous small strands of hair sticking out of his head, with his most distinguishing feature being his long pointed nose. He wore an outfit identical to his uncle's, except his shirt was green rather than red. Before long, Snively's snickers burst into full-blown laughter, causing him to fall down on the floor laughing hysterically.

Eggman stomped over to him, impaling Snively with a death glare. "I am _not_ in the mood right now, Snively, so if you value your life, you'll stop laughing _now._" he snarled.

Snively managed to compose himself and stood up, looking up at Eggman with a smirk. "So, your plans backfired and Sonic beat you again, eh?" he said mockingly. "Even the Deadly Six couldn't stop him, huh? When are you going to learn that Sonic will just keep defeating you again and again, old man?"

Eggman let out an inhuman roar and wrapped his hands around Snively's scrawny neck, lifting him bodily off the ground as he began to squeeze. Snively squirmed feebly, all mocking confidence gone for the time being.

"Well, this seems to be a bad time."

Startled, Eggman dropped an unconscious Snively before turning around to face a muscular, purple-skinned being with red body markings. He immediately drew his blaster from its holster, but the being calmly raised his hand.

"You'll find such toys to be useless against me, Doctor Robotnik," he said. Eggman hesitated, then holstered his weapon.

"How do you know my name?" he demanded. "Who are you?" The creature did a sweeping bow in seeming politeness.

"I am Culex, Dark Knight of Vanda," he said. "I am here to aid you in your battle against Sonic the Hedgehog and his Freedom Fighters."

"I don't need any help." Eggman snapped. Culex chuckled.

"Really? Because your litany of defeats and your missing mustache seem to suggest differently."

Eggman growled, but managed to control himself enough not to charge Culex directly. After a moment, Culex continued.

"I myself am unable to directly aid you, Doctor. Your dimension cannot sustain me for very long. However, I can send you some help."

Culex snapped his fingers, and a door-shaped portal filled with white light materialized in the corner of the room.

"This will take you to a pocket dimension where you will meet your allies, whose faces you may recognize. You may have failed alone, but working together, your victory is assured."

Eggman thought for a minute before giving Culex an evil smile and a nod.

"Boss, wait a minute," Cubot said. Eggman turned towards them.

"Are you sure we should trust this guy?" Orbot asked. Eggman scoffed.

"He's offering me a chance to take out Sonic for good. I am _not_ passing that up." he retorted. With that, he made his way towards the portal.

"Wait," Culex said suddenly. Eggman stopped and turned towards him. "You can't meet them looking like that."

On that note, Culex waved his hand in front of Eggman's face, and almost immediately, his mustache grew back to its original long length. Eggman felt his mustache and grinned.

"Thank you very much," he said.

With that, Eggman entered the portal.

* * *

**Wily's Fortress, Mega City, Earth 20XX  
**

Wily sat quietly in the lab in his fortress on the outskirts of Mega City, contemplating his next plan. Unlike Bowser and Eggman, he was not in a rage over his plans being thwarted. True, he was annoyed that Mega Man had defeated him, but he was also grateful to the Blue Bomber for saving his life when he discovered his high fever; it was why he helped cure the Roboenza outbreak. That didn't mean that anything had changed between them, of course.

"Well, at least you're not completely ticked off over your arch-rival like the others."

Wily stood and turned in the direction of the voice to see a purple-skinned entity unlike anything he had ever seen before.

"Who or what are you?" he asked.

"I am Culex, the Dark Knight of Vanda," the creature said. "And I already know who you are, Doctor Wily."

"Is that so?" Wily replied. "What's your business with me?"

"I am here to provide you with aid against your nemesis, Mega Man. I can help you ensure his final defeat."

"I'm listening," Wily said, a smile forming on his face.

"I myself cannot help you, as your dimension is uninhabitable to me and my kind. However, I can send you some aid."

Culex gestured to a wall nearby, and a door-shaped portal formed there.

"Beyond this portal, you will meet two individuals who have suffered similar defeats as you at the hands of their own enemies. Together, you will win, and you will all reign supreme."

"You have yourself a deal, Culex." Wily said, grinning evilly.

Without another word, Wily strode into the portal. As soon as he was gone, Culex smiled to himself.

"The stage is set. Now let's see how it plays out."

* * *

**Author's Note:  
**

Dun dun duuuuuunnnnn...

Next chapter, our Big Bad Triumvirate meets and begins their sinister plans. What does this entail for our heroes?

Please R&R. Until next time, true believers!


	3. Unholy Trinity

**- Chapter 2 -**

**Unholy Trinity**

* * *

**Pocket Dimension**

In another dimension, three door-shaped portals of white light opened in a triangular pattern, out of which Bowser, Eggman, and Wily exited. They took a minute to survey their surroundings.

The world was a large, seemingly desolate area, apparently devoid of life except for the three of them. The surface was a checkered brown, with mechanical devices seemingly growing out of the ground, and they sky was a pale greyish-green with thin clouds. After drinking in their surroundings, they turned their attentions to one another.

"Bowser?" Eggman said.

"Dr. Eggman?" Bowser said.

"Haven't seen you since all those Olympics games," they said at the same time. With that, Eggman and Wily turned to each other.

"You look familiar. Have we met?" the two humans asked one another at the same time. "No, I don't think so."

"Now that that's out of the way, I am Dr. Albert Wily of Earth 20XX," Wily said.

"I am King Bowser Koopa of the Mushroom World," said Bowser.

"And I am Dr. Ivo Robotnik of Mobius," Eggman said. "But you can call me Eggman."

"So you two are the guys that that Culex guy said were gonna help me, huh?" Bowser said. "From what I've heard, the three of us all have something in common: a long, long list of humiliating defeats at the hands of our is that cursed plumber Mario!"

"I too have suffered countless losses at the hands of that pesky hedgehog Sonic!" Eggman spat.

"And that darn Mega Man always finds some way to ruin my plans too!" Wily yelled.

"That stupid hero is such a pain in the neck!" the three villains declared in perfect unison. After a moment, they all exchanged looks before smiles formed on their faces. Before long, all three of them broke out into maniacal laughter.

"Looks like we're gonna get along just fine," Bowser said, Eggman and Wily nodding their affirmation.

And at that very moment, an unholy trinity was born.

* * *

**Bowser's Skull Egg Zone  
**

A few hours later, in the pocket dimension, Bowser, Eggman, and Wily were working with their various assorted minions to construct a base of operations for their multi-dimensional plans. They had named the dimension "Bowser's Skull Egg Zone" (their compromise between Bowser's "Bowser Zone," Eggman's "Egg Pocket Zone," and Wily's "Skull Secret Zone"), or the "BSE Zone" for short. As they had discovered, the BSE Zone had a different flow of time than the Mushroom World, Earth 20XX, or Mobius, allowing hours to pass in the zone while mere seconds passed in the other worlds.

The trio had opted to build a base in the BSE Zone because of its unique space-time properties, allowing them to accomplish several hours of work in mere seconds. Furthermore, as Mario, Sonic, and Mega Man had no idea of the existence of their current alliance, the zone was a perfect way to develop and further their plans without interference. Culex had even given them a mystical crystal from Vanda that allowed them to open the gateways to and from the BSE Zone at any time.

In the very center of the zone was a massive castle built combining the trio's different resources, and adapted to their various different tastes. For example, the front door of the castle was in the shape of a massive egg, but with a large stone statue in the shape of Bowser's face set in around the door. Adorned all around the castle were flags bearing all three of their insignias: a stylized red drawing of Bowser's face, a similarly stylized yellow-and-black drawing of Eggman's face, and Wily's trademark skull insignia.

To top it all off, Eggman and Wily had combined their technological know-how. Eggman had a machine from his world known as a Roboticizer, which could turn biological creatures into his obedient robot slaves, while Dr. Wily could create powerful and intelligent robots called Robot Masters. Combining their knowledge, they created a modified Roboticizer that could turn living beings into what they called "Roboticized Masters"; both of them noted that the process sounded familiar to them somehow, but they couldn't quite place it.

Now it was time to put their plans into action. And they knew just how to start.

* * *

**Author's Note:  
**

Archie Comics fans will likely notice the nods I made to _Sonic & Mega Man: Worlds Collide_. If I'm not mistaken, everyone from both series except Sonic himself forgot about the events of the crossover beyond vague recollections; if I am, then oh well, they _did_ forget here for the sake of the plot.

Next chapter, we're finally introduced to our heroes, but the meeting may not be as peaceful as you might expect.

Please R&R. Until next chapter...


	4. Set-up

**- Chapter 3 -**

**Set-up**

* * *

**The Castle, Bowser's Skull Egg Zone **

Within the massive throne room of their castle, Bowser, Eggman, and Wily sat around a table, orchestrating their sinister plans.

"Naturally, our first step is to get rid of our respective enemies," Eggman said, stroking his mustache. "With them out of the way, taking over our respective worlds is going to be a snap."

"You don't need a diploma to know that, Doc," Bowser said sarcastically. "Question is, how exactly are we gonna do it?"

The three were silent for a few moments before Wily snapped his fingers.

"I've got it!" he exclaimed. "How about we set them up?"

Bowser and Eggman turned towards him.

"What kind of set-up are you talking about, Wily?" Eggman asked. Wily stood, grinning.

"It's simple, really," he began. "I have my Copybot, Eggman has his Metal Sonic, and Bowser's son, Bowser Jr., can turn into a duplicate of Mario, correct? Well, what if Mario, Sonic, and Mega Man had a misunderstanding and got into a fight? With any luck, they'll destroy each other!"

For two minutes, Bowser and Eggman considered it. Finally, Eggman broke the silence.

"So, we set them up and hope they'll kill one another?" he said. "What a cliché."

"I know, but right now, it's all we've got, Eggman," Bowser said. "Unless you have a better idea."

Eggman readjusted his sunglasses before letting out a resigned sigh. "No, I do not."

"Then let's just go with it for now," Bowser said.

"Let's go get the minions ready," Wily said. "We'll start with Mega Man."

Bowser held up his hand. "Hold on," he said. "Before we go, I need to ask you something, Eggman."

"Ask away."

"How are those new weapons I commissioned from you coming along?"

Eggman smirked. "They're still in the developmental stages, Bowser. I just need to work a few bugs out here and there, and they'll be ready for combat."

Bowser grinned, showing a mouthful of razor-sharp teeth. "Excellent."

* * *

**Light Labs, Mega City, Earth 20XX **

Rock Light, better known to the world as Mega Man, lay contentedly on his bed, looking at the ceiling. As he was not in combat right now, he was wearing his civilian clothes, consisting of a blue-and-white T-shirt and black shorts with blue boots.

Things had been relatively quiet since the Roboenza outbreak. Wily had disappeared after his recovery in the hospital, and try as they might, they were unable to find any trace of him. Rock wasn't particularly bothered by that, however; whenever Wily tried another scheme, he would be there to stop him.

Suddenly, a cacophony of crashes and shouts resounded through the building, before a high-pitched female scream cut through it. Rock bolted upright in bed.

_It's coming from the lab!_ Rock thought frantically.

Wasting no time, Rock sprang up off the bed and was surrounded in a white light. Within seconds, he had shifted to his combat form: a cyan-and-blue bodysuit and a blue helmet with circular ear pieces and a blocky design extending across the scalp.

Mega Man threw his door open and bounded down the steps, reaching the lab and making his way in. He stopped short when he saw the source of the noise.

Standing before him was a short, stocky, human-like man with a bulbous nose and bushy mustache. He was dressed in a long-sleeved shirt, overalls, work boots, gloves, and a newsboy-esque cap with a monogrammed "M" on it. His eyes were a piercing red, but what was really bizarre was that his entire body was blue and almost translucent. In his hand, he held what appeared to be a giant paintbrush.

Next to him was a robot built in the shape of a humanoid hedgehog. Its metallic "skin" was blue, though its arms, fingers, and muzzle were silver and its hands were yellow. Its feet had the appearance of red sneakers, and its eyes were a piercing red with black sclerae. It also had a large black hole in its abdomen, lined with yellow. For some reason, Mega Man felt as if he had seen the hedgehog robot before.

What really caught his attention, however, was what they had in their hands: a little girl with long blond hair tied in a ponytail with a green ribbon, wearing a red dress and matching Mary Jane shoes. It was Mega Man's sister, Roll Light.

"Roll!" Mega Man shouted, already converting his right arm into his Mega Buster and aiming at the duo. "Get your hands off of her!"

The blue man with the paintbrush simply chuckled before raising his hand to his face and pulling down his left eyelid. To drive his point home even further, a long red tongue flapped out of his mouth in a loud raspberry.

"You want her so bad, Mega Twerp?" the hedgehog taunted. "Then come and get her!"

With that, the paintbrush man pointed his brush at the wall, and a thick, goopy, rainbow-colored paint-like substance sprayed out of it and splattered on the wall, forming a giant stylized glowing "M." With that, the hedgehog grabbed the man's arm and a burst of flame erupted from his back, launching them both through the "M" at high speed with Roll in their clutches.

"ROCK, HELP ME!" Roll managed to scream before they disappeared through the "M", which Mega Man realized was some form of portal.

Wasting no time, Mega Man dove through the portal after them, exiting on the other side of the house. Looking to his left, he saw the hedgehog and painter flying away at high speed. With that, he put his left index finger and thumb to his mouth and let out a loud whistle. Almost immediately, a robotic dog came dashing out of a doghouse on the side of the yard. Mega Man's faithful canine companion, Rush.

Rush was covered in red armor with a helmet resembling Mega Man's, with his four legs attached to his body by pink-and-yellow circular joints, along with red pointy ears and paws, a white segmented tail, a tan face, brown nose, blue eyes, and pink limbs, neck, and midsection.

"There's no time to lose!" Mega Man yelled as soon as Rush reached him. "Rush Jet!"

Rush let out a bark in response and converted his body into a flat, jet-powered hoverboard. With that, Mega Man leapt onto Rush's back and took off after Roll's kidnappers.

* * *

**Mega City, Earth 20XX  
**

Metal Sonic and Shadow Mario looked back over their shoulders. Just as they had predicted, Mega Man was in hot pursuit of them.

"It's working, Metal!" Shadow Mario declared with glee. "We just need to keep ahead of him!"

"With my speed, that'll be a cinch." Metal Sonic replied. Roll, still clutched firmly in Metal Sonic's other hand, glared at her captors.

"You won't get away with this!" she shouted. "Rock will save me, and when he does, you two are gonna wish you were never born!"

Metal Sonic turned his gaze on Roll and tightened his grip on her arm, causing her to let out a small yip of pain.

"Kid, you're supposed to be bait," he said, slightly annoyed. "Start acting like it."

"Why don't you try and _make_ me?" Roll spat. Before any of them could say anything more, a glowing white portal formed in front of them.

"Here it comes!" Shadow Mario yelled. "Get ready!"

Metal Sonic clenched his body into a brief fetal position, and the sound of a high-speed turbine echoed as the jets in his back charged. Firing off the jets, Metal Sonic shot off in a massive burst of speed, creating a small sonic boom as he flew directly into the portal. Mega Man and Rush unflinchingly followed them through the portal, which sealed up behind them shortly after.

* * *

**The Castle, Bowser's Skull Egg Zone  
**

Shadow Mario and Metal Sonic burst out of the portal on the castle grounds, where Bowser, Eggman, and Wily were waiting with several of their minions. Roll's face contorted with anger the minute she saw Wily.

"Dr. Wily!" she shouted. "I _knew_ you were behind this!"

Wily snickered. "I can't take all the credit this time, Roll," he said, gesturing to Bowser and Eggman. "As you can see, I'm not alone."

Roll looked at Bowser and Eggman for a minute before turning back to Wily. "What are you gonna do to me?" she demanded.

"Isn't it obvious?" Eggman said. "You see, my girl, we've joined forces to defeat our respective arch-nemeses and dominate our worlds. The ones who captured you are built in the image of said enemies."

Roll looked from Metal Sonic to Shadow Mario and back again, and the proverbial light bulb lit up above her head.

"So, when Rock runs into your actual enemies, he'll think they're the ones who kidnapped me and try to kill them," she said in silent horror.

"That's right, kid," Bowser said. "With any luck, Mario, Sonic, and Mega Man will kill each other."

"You're _sick_!" Roll screamed, struggling against Metal Sonic and Shadow Mario's iron hold.

"That's a matter of opinion." Eggman said. With that, the three gestured towards their minions.

"Take her to the dungeon," they all said in perfect unison. At that, three minions, one from each of the trio's armies, stepped forward.

Bowser's minion was a big, muscle-bound Koopa Troopa, at least twice the size of a regular Koopa Troopa with a dark green shell; it was a Super Troopa (1).

Eggman's minion was one of his latest series of Badniks, the Egg Swats, a combination of Egg Pawn and Swatbot which featured the domed gray heads of the Swatbots, albeit with a red spike on the top of the head, spiked shoulders, and the bulky round bodies of the Egg Pawns, complete with a red, gray, and orange color scheme.

Finally, Wily's minion was a Sniper Joe, featuring a gray cannon for a right arm and a matching gray left hand which held a thick white shield. The rest of its body was a dark green, with the exception of its arms and feet, which were black. Instead of a face, it had a black visor-like opening with one red eye.

Shadow Mario and Metal Sonic obediently handed Roll over to the three minions, the Super Troopa and Egg Swat taking one of her arms each, and the Sniper Joe pressing its gun against her back. The minions proceeded to drag Roll off to the dungeon; though she struggled and cried out the entire way, she was no match for them.

"Now that that's out of the way, what about Mega Man?" Metal Sonic asked. "He followed us through the portal."

"Not to worry, Metal," Eggman said. "We reset the portal's destination for Grass Land in the Mushroom World as soon as you went through. It's also been pre-programmed to do the same for Sonic. That's where things will play out."

"Now that that's out of the way..." Wily said, "Copybot!"

As soon as those two words were out of the mouth, a blue pillar of light shot down and landed right in-between Shadow Mario and Metal Sonic. As soon as it hit the ground, it coalesced into a figure resembling Mega Man almost exactly, except for red eyes and a purple scarf around his neck.

"On the scene!" Copybot declared triumphantly before turning to the trio. "You rang, Dr. W.?"

"Yes," Wily said. "You are to go with Bowser Jr. to Mobius and capture Sonic the Hedgehog's parents, Jules and Bernie Hedgehog. Bring them back here. Use force if necessary, but we want them brought back alive."

"You got it, Doc," Copybot replied before turning to Shadow Mario. "Let's go, kid. Try not to get in my way."

Shadow Mario just rolled his eyes before another white portal opened before them. Copybot and Shadow Mario promptly went through the portal, leaving Metal Sonic behind.

"Metal, you stand by until they get back," Eggman said. "When they do, you and Copybot will go to the Mushroom World and capture Princess Peach."

"Yes, sir," Metal Sonic said.

* * *

**Tommy Turtle Memorial Hospital, New Mobotropolis, Mobius (2)  
**

Through the bustling streets of New Mobotropolis, a blue-and-tan hedgehog with green eyes, white gloves, and red sneakers with white straps and golden buckles made his way to the local hospital. By his side was a small yellow-and-white fox with two tails, white gloves, and red-and-white sneakers. Two of the Knothole Freedom Fighters, Sonic the Hedgehog and Miles "Tails" Prower.

It had been a few months since they, alongside the Arctic Freedom Fighters and Silver the Hedgehog, had managed to capture and subdue Mecha Sally at the Northern Tundra and bring her back to the city, where NICOLE had kept her imprisoned until Sonic's Uncle Chuck, using the single sprig of the Krudzu that they had procured at Albion as a base, had managed to deroboticize her. Shortly after, they had discovered that Ixis Naugus was the one who had facilitated NICOLE's brief exile from the city, using Mina Mongoose's music as a conduit to do so, and managed to force him out and reinstate Elias Acorn as the king once more. Then, just a few weeks ago, they had to deal with the near-destruction of Mobius at the hands of the Deadly Six, who had usurped control of Eggman's operations on the newly discovered Lost Hex.

Amidst all these fights and hardships, however, there was some good news. First, it was shortly after they returned from the Lost Hex that Bunnie Rabbot had returned from her self-imposed exile, realizing that she was at her best when with the other Knothole Freedom Fighters, as well as discovering that the process that Naugus used to revert her roboticized limbs back to normal was apparently only temporary, the limbs having returned to their robotic state through a process Bunnie simply described as painful. Nonetheless, they were all glad to have them back.

On top of it all, they had recently learned from Dr. Qwack that Antoine D'Coolette, who had been in a coma for a long time after being heavily injured by a self-destructing Metal Sonic, had finally awakened and was slowly but surely starting to recover. He and Tails were going to visit him right now.

With that, the two friends made their way through the hospital doors and straight to Antoine's room, where they were pleasantly surprised to see the French coyote sitting upright unassisted, a crown of bandages hiding his blonde hair and an IV line inserted in his right arm. Seated next to him was Bunnie, who held his hand gently yet tightly in her organic right one, and had her trademark cowboy hat in her lap.

"Hey there, Ant," Sonic said, smiling happily. Bunnie and Antoine both turned towards them and smiled back. "How ya feeling?"

"I've certainly been better, but I'll live," Antoine replied, his thick French accent still the same.

"The doc says he can sit up and do some things on his own, but it'll take some time before he's completely independent again." Bunnie said.

"Well, it's still progress, anyway," Tails said. "At least you're doing okay."

At that moment, however, a female lynx with black hair wearing a purple dress materialized out of nowhere in the room. Everyone turned to face the figure of NICOLE.

"Sonic! I'm sorry to interrupt, but we've got trouble!" she declared. Sonic snapped to attention.

"What's going on, NICOLE?" he asked.

"Two mysterious figures have just surfaced near your house. I think they might be after your parents!"

Sonic looked at her in shock for a moment, then grabbed Tails by the arm and darted out the door without a word. After a moment, Antoine gave a small smile.

"Some things never change," he remarked.

* * *

**Sonic's House, New Mobotropolis, Mobius  
**

Sonic and Tails reached Sonic's home in record time, and were greeted with the shocking sight of Jules and Bernie Hedgehog being dragged out the door by a blue human-like figure and a blue robot with a purple scarf.

"Mom! Dad!" Sonic shouted, but hesitated when he saw the blue plumber.

"Mario? Is that you?" he asked, recognizing him from those Olympics tournaments they and their respective friends had partaken in on Earth, or what Mario and his friends called "the Real World." "Why are you doing this?"

"Because it's fun, Spikeball!" Shadow Mario shot back mockingly. Jules began to struggle against Copybot.

"Get your hands off of me, you-" he managed before Copybot drew back his fist and slammed it into his temple, beating a small dent into the side of the Robian's head. Sonic let out an angry growl and made as if to attack Copybot, but hesitated. Something seemed familiar about him, but he couldn't place it...

"So, Sonic," Copybot asked, "you mind explaining to me how exactly your dad could have kids if he's a robot? Naw, never mind; I don't wanna know."

"It's none of your business!" Sonic snapped. "Get your hands off of my parents and get out of my city before I kick both of your butts!"

"Yeah, I don't think that's gonna happen, Spiky," Shadow Mario said mockingly. "You ain't exactly in a position to demand anything of us-"

But no sooner had those words come out of his mouth than what appeared to be an elastic sledgehammer burst out of the bushes nearby and slammed into Copybot's face with the force of a pile driver, knocking him away and off of Jules.

"That's what you think, buddy!" a new voice declared as the sledgehammer retracted into the bushes. Everyone there turned toward the bushes to see a familiar figure leap out; it looked similar to Metal Sonic, except he had green eyes rather than red, a black, gold, and gray, paint job, and instead of a hole in its stomach, it had a small Power Gem. Sonic and the others recognized him as Shard, the original Metal Sonic.

"Just in time, Shard!" Sonic declared, giving the robo-duplicate a thumbs-up. Shard grinned before darting forward and positioning himself between Copybot and Jules, morphing the sledgehammer in his left arm back to a generic arm cannon.

"Mega Man!" Shadow Mario shouted, realizing that directly referring to Copybot as such in front of Sonic would jeopardize the plan. "We'll have to make do with one hostage! Let's cut our losses and scram!"

With that, he fired a stream of green goop at Shard, which splattered all over him. Shard barely had time to react before he started to spark, the paint seeping into his systems and gumming up his works.

"Dang it!" he shouted. Taking advantage of the moment, Shadow Mario and Copybot grabbed Bernie and took off.

"NO!" Sonic screamed, seeing them flee. He shifted his gaze between Jules and Shard, trying to decide what to do.

"Sonic!" Jules shouted, getting to his feet and clutching the side of his head. "Don't worry about us! Save your mother!"

"He's right, Sonic!" Shard agreed as he collapsed to one knee. "Just go! We'll be okay!"

Sonic nodded to them, and then to Tails. "Let's do it to it, buddy!"

Tails nodded in agreement, and together, the two ran after Bernie's kidnappers. They didn't get far before a door-shaped portal appeared in front of them out of nowhere, startling numerous passersby on the streets.

"_GET BACK HERE!_" Sonic screamed in a rage before he and Tails jumped into the portal after them, said portal sealing up behind them.

* * *

**The Castle, Bowser's Skull Egg Zone  
**

Shadow Mario and Copybot rematerialized in the courtyard, depositing Bernie none too gently in front of their bosses. Bernie scowled when she saw Eggman.

"I knew you had something to do with this, Robotnik," she spat.

"Quite right, Bernadette," Eggman replied. "I'd love to stay and chat with you, but we have a schedule to keep. Boys?"

On that note, the same Super Troopa, Egg Swat, and Sniper Joe that took Roll to the dungeon grabbed Bernie and proceeded to do the same with her, with Bernie struggling in vain all the way before Eggman turned to Shadow Mario and Copybot.

"And where's Jules?" he asked. Shadow Mario hesitated, then spun in a circle, his shape morphing into that of a short Koopa before pulling a black bandana with a drawing of a nose and mustache on it away from his face, revealing his true form of a Koopaling with short horns, red hair in a ponytail, beady eyes, and an overall strong resemblance to Bowser; Bowser's son Bowser Jr.

"It's not our fault," he insisted. "Some kind of rogue Metal Sonic showed up and tried to stop us. We had to cut our losses and leave Jules behind."

"Rogue Metal Sonic?" Eggman asked, then let out an annoyed growl. "Shard!" he turned to Metal Sonic. "I thought you destroyed him!"

"They must have found his remains and repaired him," Metal Sonic said simply. "When we meet next time, he won't be so lucky."

"For now, it's time for the final stage of the plan," Bowser cut in sharply. Pulling a remote control out of his pocket, he pressed some buttons, and the portal flickered for a minute.

"The portal's set to send you to Toad Town in the Mushroom Kingdom," he said. Eggman and Wily nodded.

"Metal, Copybot, you two go and get Peach," Eggman said. The two villainous robots nodded.

"Junior, you go too, and make sure you stay as Shadow Mario," Bowser said.

"As soon as you have Peach, the three of you split up, track down Mario, Sonic, and Mega Man, and lure them to the rendezvous point where they'll fight. As soon as they're in position, escape their lines of sight and make sure you remain conspicuous afterwards. Understand?" Wily said. The trio nodded, Bowser Jr. pulling his bandana back over his face and morphing back into Shadow Mario.

"Let's go," Copybot said. "Like I said before, you two clowns try not to get in my way."

"The feeling's mutual, pal," Metal Sonic shot back before the three doppelgängers entered the portal.

"Things are going swimmingly, my friends," Wily declared, grinning evilly with Bowser and Eggman following suit.

"Soon, it will be game over for them." Eggman said.

"We'll see them in The Underwhere." Bowser hissed.

With that, the three broke into a trinity of evil laughs.

* * *

**Author's Note: **

(1): The Super Troopa here is _not_ the same as the caped Super Koopas from _Super Mario World._ I mean the Super Troopas that appeared in a few episodes of _The Super Mario Bros. Super Show!_.

(2): In this story, at the end of _Worlds Collide_, Sonic managed to use his Chaos Control to restore Mobius to exactly how it was before the Super Genesis Wave.

Woo, that was the longest chapter yet! I originally intended to have Mario's world featured in this chapter as well, but then it would've been too long. Don't worry, our favorite plumber will finally make a personal appearance next chapter, in the lead-in to the three-way fight.

And BTW to my anonymous reviewer, yes, this story is partially based on MasterZonafer13X's series, but I got the idea while he was still calling it _Ninsegacom GT Adventures Z_; I didn't know he renamed his series _Heroes United_ until recently.

Please R&R. Until next time.


	5. The Plan Comes Together

-** Chapter 4 -**

**The Plan Comes Together  
**

* * *

**Author's Note: **

For those of you wondering about the title change, I got a message from LeonidasZonafer on my Deviantart account about this fic. Turns out he's working on a similar series called _Heroes United_ and he asked me to change the fic's name to avoid confusion.

Funny thing is, part of my inspiration for this fic was from one of his works, _Ninsegacom GT Adventures Z_ I believe it was called, but I had no idea he was working on a series called _Heroes United_ until recently.

Oh, well. And I forgot to mention this earlier, but the storyline here also takes place after _Luigi's Mansion: Dark Moon, Wario Land: Shake It!,_ and _Donkey Kong Country: Tropical Freeze. _Why is this relevant? You'll see...

And now, for the moment we've all been waiting for: Mario and his friends finally make an appearance! Yay!

* * *

**Toad Town, Mushroom Kingdom, The Mushroom World  
**

The sun shone brightly on a two-story house, painted yellow with a red roof, a Star antenna, and a chimney resembling a pipe. On the lawn was a clothesline, as well as a sign sunk into the ground that declared "Mario Bros. Plumbing" in big red and green letters.

Stretched out on lawn chairs were two plumbers. They were none other than the Mario Bros. on the sign, Mario and Luigi.

Mario, the older of the two, was short and stocky, had brown hair, blue eyes, a bulbous nose, and a thick black mustache shaped in six upside-down bumps. He wore a red long-sleeved shirt under blue denim overalls with golden buttons, along with white gloves and brown work boots with tan bottoms. To complete the look, he wore his trademark red cap, monogrammed with a red "M" within a white circle.

Luigi, the younger brother, was taller and thinner than Mario, but had the same eyes and hair color, though his mustache was straighter and tilted slightly upwards. He was dressed identically to Mario, albeit with a green shirt and darker blue overalls, and his own hat was green and monogrammed with an "L."

It had been two months since they thwarted Bowser's attempts to conquer the Sprixie Kingdom and since Luigi foiled King Boo's operations in Evershade Valley. In that time, they hadn't heard anything out of either evil king, so they decided to take the opportunity to relax.

Suddenly, they heard a high-pitched bark, and turned to see a white, semi-transparent ghostly dog with a long tail and red collar phase through the door of their house. The brothers looked up and smiled; it was Spooky (1), the Polterpup Luigi had taken as a pet from Evershade Valley.

"Hey, boy!" Luigi said happily, holding his hand out to the ghost dog. Spooky let out a cute yip and bounded towards his master, jumping on his lap and licking his face vigorously as if he hadn't seen Luigi in years.

Mario gave a small smile, happy that Luigi had seemingly finally conquered his long-running fear of ghosts. Though he would have preferred a living, flesh-and-blood dog, he couldn't deny that Spooky was cute and fun to be around.

"Master Mario! Master Luigi!"

The two brothers sat upright and turned towards the direction of the voice. Running up the path to their house was a short Toad wearing a beige mushroom cap with brown spots, pince-nez glasses with black rims, a puffy white mustache, a red bow tie, and a light purple vest with gold buttons under another purple vest with gold trim, complete with white bottoms and brown, padded booties. In his hand was a brown walking stick, topped with a brown mushroom cap with beige spots. It was Princess Peach's longtime steward, Toadsworth.

The Mario Bros. immediately jumped to their feet, expecting trouble. Toadsworth reached them, his face red as a tomato and in a state of panic.

"Horrible! It's horrible! They attacked the castle! It all happened so fast! I couldn't..." Toadsworth babbled.

"Toadsworth, calm down!" Mario said, grabbing the elderly Toad by his shoulders. "Now, just slow down a bit and tell us what's the matter."

After a moment, Toadsworth took a deep breath and managed to compose himself with an effort. "It's the princess!" he exclaimed. "She's been kidnapped!"

"Again?!" Mario and Luigi said in perfect unison.

"Was it Bowser?" Mario asked. Toadsworth shook his head.

"No, not this time," he said. "It was a blue hedgehog, as well as some human boy wearing a blue bodysuit."

"Blue hedgehog?" Luigi asked, recalling something. "Mario, you don't think it was..."

"Yeah," Mario said. "It must have been Sonic. But why would he want to kidnap Peach?"

"Sonic?" Toadsworth asked. "That chap that we competed against in the Real World's Olympic Games? You're right, Master Mario. This doesn't seem to add up."

"Well, not to worry, Toadsworth," Mario said, getting to his feet. "We're gonna get to the bottom of this. Do you know which way they went?"

Toadsworth nodded. "Yes, they were headed for Grass Land."

"Don't worry, Toadsworth," Luigi assured. "They won't get far."

With that, they turned to Spooky.

"Hold down the fort 'til we get back, okay, boy?" Luigi said to the Polterpup. Spooky barked in response, clearly meaning "yes."

Making a quick stop in the house to retrieve their hammers, Mario and Luigi departed, headed for Grass Land.

* * *

**Grass Land, Mushroom Kingdom, The Mushroom World  
**

Grass Land truly lived up to its name: open plains of grass as far as the eye could see, with the small village of Rose Town (3) in the distance. And it was over these grass plains that Metal Sonic and Copy Robot flew, clutching their prize: a beautiful young woman with fair skin and long flowing blonde hair, wearing a floor length pink dress with a sapphire brooch and matching earrings, along with a crown encrusted with rubies and sapphires, white elbow-length evening gloves, and red heels. It was none other than Princess Peach.

Peach struggled against Metal Sonic's iron grip, but no matter how she tried to pry away his fingers, she simply could not break free.

"You won't get away with this!" she shouted. "Mario _will_ come for me, and then you'll be sorry."

"We know that, 'Your Majesty'," Copy Robot retorted, saying "Your Majesty" with more than a bit of bite and sarcasm. "That's what we're counting on, y'see."

Peach looked at him in confusion. "What do you mean?"

Before they could say anything more, out of nowhere a hammer came flying and slammed into Metal Sonic's head, just missing Peach. He recoiled, unwittingly loosening his grip on Peach in the process.

Peach saw her chance and took it. Pulling her parasol out of the folds of her dress, she swung it like a baseball bat, slamming it across Metal's face full force.

Sparks and static danced across Metal's vision, and he lost his grip on their captive. Peach didn't fall far before Mario shot into the sky like a rocket, catching her in his arms.

"Gotcha!" he shouted as they fell to the ground, landing safely. Luigi ran up behind them as Metal Sonic and Copy Robot landed.

"Why are you doing this, Sonic?" Mario demanded. "I thought you were a hero!" Metal Sonic felt a deep sense of revulsion at again being compared to his goody-two-shoes organic counterpart, but kept his feelings hidden for the sake of the plan. Instead, he simply shrugged his shoulders.

"I _was_ a hero, plumber," Metal said. "But what can I say? Being evil is just so much more profitable than being good. And more fun! (2)"

"So what if you got the princess, ya mustache morons?" Copy Robot taunted. "Our plan is still underway."

"Plan? What plan?" Luigi demanded.

"Maybe if you catch us, you'll find out!" Metal Sonic declared before grabbing Copy Robot and taking off; even if they failed to capture Peach, they could still lure the Marios into the trap.

Mario turned to Peach. "Listen to me," he said. "We'll take care of Sonic and his friend. You go back to the castle where it's safe."

Peach hesitated, then nodded. With that, Mario reclaimed his hammer, which had embedded itself in the ground not too far away, and took off with Luigi after the villains.

* * *

**Grass Land, Mushroom Kingdom, The Mushroom World  
**

Shortly after Metal Sonic and Copy Robot made their escape, a loud, urgent beeping sounded. Metal popped open his chest plate to reveal a communicator and speakerphone, proceeding to press a button on it.

"What is it?" he asked.

"_It's me,_" came the voice of Bowser Jr. "_Papa and the doctors just informed me that Sonic and Mega Man have just arrived in this world; Sonic's to the west, Mega Man's to the east. We have to split up here to lure them to the rendezvous. I've got Sonic._"

"Okay," Metal Sonic replied. "Copy Robot, you keep Mario on your tail. Leave Mega Man to me."

Copy Robot nodded before letting go of Metal and dropping to the ground, Metal Sonic heading eastward. Copy Robot hesitated for a second.

"There he is!" an Italian-accented voice shouted. Copy Robot looked over his shoulder, and sure enough, Mario and Luigi were running towards him. Grinning evilly, he began running, headed north.

On his end, Bowser Jr., still in his Shadow Mario guise, watched from the side as Sonic and Tails exited a portal that just materialized on the side of one of the various green mountains with beady black eyes. The two looked around in confusion.

"What is this place?" Tails asked.

"Beats the heck out of me." Sonic replied. Shadow Mario decided now would be the perfect opportunity and jumped out in front of them.

"You're in my world now," he said. "The Mushroom World, to be exact. It's a lovely place to die!"

"Mario!" Tails shouted. Sonic's green eyes flashed in anger.

"Where's my mother?!" he demanded, taking a threatening step forward. "Answer me, dirt bag!"

"You really wanna know?" Shadow Mario taunted. "First, you're gonna have to catch me!"

With that, he flicked the Magic Paintbrush, spreading an oil slick-like goop on the ground in front of him, which he proceeded to run over and skate on, the goop giving him a speed boost.

"Don't let him get away!" Tails shouted.

With that, Sonic took off running after Shadow Mario, with Tails flying after him.

Meanwhile, Metal Sonic had shown up just in time to witness Mega Man and Rush, the latter still in jetboard form, exit the portal on their end. Wasting no time, Metal launched his telescopic arm, the fist just missing Mega Man; of course, that was his intent. Mega Man turned in his direction, and his face immediately clouded with anger.

"You!" he shouted. "Where's Roll? What have you done with her?!"

"Why don't you follow me and find out?" Metal Sonic said mockingly as he retracted his arm and darted off.

"We can't lose him!" Mega Man yelled. "Let's go, Rush!"

Rush barked in agreement before firing his jets and taking off after Metal Sonic.

* * *

**Grass Land, Mushroom Kingdom, The Mushroom World  
**

It wasn't long before Metal Sonic, Shadow Mario, and Copy Robot reached the designated point: an open field a mile or so outside of Rose Town. Right on cue, a Warp Ring with a white center appeared in front of them, their path back to the BSE Zone. Before they could go through, however, a strange figure jumped out and landed in front of them.

The three doppelgängers took a moment to look the newcomer over. It was a tall, robotic dinosaur with lime green skin, a white chestplate and deep blue eyes with black sclerae, a big metal snout, green cylindrical forearms, and a dark green helmet resembling Mega Man's with a white visor and circular earpieces sitting atop his head. Along the back of his neck was a row of red metal spines, a red turtle-like shell and white wing-like protrusions on his back, and tan knee-length boots, with a long powerful snake-like tail. After a moment, they realized what it was: a roboticized Yoshi.

"So, you must be a Roboticized Master?" Shadow Mario asked, recalling the process being briefly mentioned during the BSE Zone's construction.

"Yes," said the robot Yoshi. "I am Yoshi Man (1), the first of the Roboticized Masters. I was one of several individuals who were captured from the three worlds to serve this purpose while you three were out."

"So why are you here?" inquired Metal Sonic.

"That's not important right now," Yoshi Man replied. "You three, return to base. Mario, Sonic, and Mega Man will be here any minute."

"He's right, guys," Copy Robot said. "Let's amscray."

On that note, the three jumped through the Warp Ring one after another, the Ring vanishing behind them. As soon as it did, Yoshi Man ducked into a cluster of bushes nearby, his green coloration allowing him to blend in effortlessly.

Yoshi Man was just in time, for no sooner had he concealed himself in the bushes than Mario, Luigi, Sonic, Tails, Mega Man, and Rush all came running up from three different directions. The six heroes all skidded to a stop at the sight of each other, their eyes darting back and forth between one another in silent anger.

"So, you've got a new partner, huh?" Mario, Sonic, and Mega Man all declared in perfect unison. "Well, they're not gonna help you here!"

Mario and Luigi brandished their hammers, Sonic cracked his knuckles and tapped the toes of his sneakers against the ground, Tails landed from flight mode and bent his knees in a fighting stance, and Mega Man jumped to the ground and brought out his Mega Buster while Rush shifted back to his normal form, growling and bending low to the ground as if to pounce.

The fight was on.

* * *

**The Castle, Bowser's Skull Egg Zone  
**

Metal Sonic, Shadow Mario, and Copy Robot all exited the Warp Ring inside the meeting room in the castle. Looking around, they saw their respective masters, as well as all of their fellow minions, assembled in front of a large video screen, the image depicting Mario, Sonic, Mega Man, and their respective sidekicks about to fight.

"What's going on?" Shadow Mario asked, pulling down his bandana and morphing back to Bowser Jr. Bowser turned around and grinned.

"You've already met Yoshi Man, right?" he asked. Bowser Jr. nodded.

"Well, when the roboticization process was complete, we installed audio/visual equipment so we can see and hear everything he does," Eggman explained.

"So that's why you sent him through," Metal Sonic realized. "So we could watch them destroy each other."

"Exactly," Wily said. "And Yoshi Man will finish off whoever's left standing."

On-screen, the tension exploded, and Mario, Sonic, and Mega Man all charged each other, their fists balled and raised to punch.

"Here we go!" Bowser exclaimed. "The moment of truth!"

With that, the villains all settled back to watch the show.

* * *

**Author's Note:  
**

(1): Luigi does take a Polterpup home with him at the end of _Luigi's Mansion: Dark Moon_. I named him Spooky for this fic, since the pup was unnamed there.

(2): A quote taken from Warp Darkmatter of the _Buzz Lightyear of Star Command_ movie.

(3): Any of you who have played _Super Mario RPG_ will recognize Rose Town.

(4): I named him Yoshi Man as per Robot Master naming conventions.

Well, the three-way fight has begun. Next chapter, we'll see how it pans out.

Please R&R. Until next time, everybody!


	6. Three-Way Fight

**- Chapter 5 -**

**Three-Way Fight **

* * *

**Author's Note: **

Whenever I feel that there's a certain song or BGM that fits a certain scene, I'll post a link to that song here. You'll know what song plays when and when it stops by an asterisk marking the beginning of the scene.

* _Super Smash Bros. Brawl_ Boss Battle Song 1: www. youtube. com watch?v= ZK4FmoFUijI

** _Kingdom Hearts II_ Vim and Vigor: www. youtube. com watch?v= B0mwOjhsDgY

*** _Mario & Luigi: Partners in Time_ Boss Battle: www. youtube. com watch?v= X1LkQngjv7E

The site won't let me post the full link, so just copy and paste to your browser from here and delete the spaces. Okay, in the immortal words of Sonic, let's do it to it!

* * *

**Grass Land, Mushroom Kingdom, The Mushroom World  
**

*Mario, Sonic, and Mega Man reached each other and threw a punch at the same time, their fists slamming together in mid-air (1). The force of the blows knocked them backwards about a foot, but the three recovered quickly.

Mario instantly sprang into action, jumping into the air with his fist raised upwards in his Super Jump Punch attack. His extended fist crashed into Sonic's jaw full force. Sonic fell back, but as he did, he lashed out with one foot, catching Mario in the stomach and sending the red plumber backwards.

While he was focused on Mario, Sonic seemingly didn't notice Mega Man readying his Mega Buster, glowing as he readied a Charge Shot. As soon as the charge was complete, Mega Man took aim at Sonic's back and fired.

However, as soon as the lemon-shaped energy ball left the Mega Buster's barrel, the quills on Sonic's back stiffened, and he twisted around to see the attack coming. With lightning speed, Sonic darted to the side, and the energy bullet slammed into Mario instead, knocking him on his back.

"What the?" Mega Man said. "How did you-?"

"My quills were tingling before you even shot at me, buddy (2)," Sonic said. "It's not the first time it's saved my behind."

As soon as he was finished talking, however, Sonic felt something tap his shoulder. He turned around just in time for Mario to punch him right in the face. Almost as soon as his fist made impact, Mario bent down level to the ground and tackled Sonic, driving his right shoulder into the Blue Blur's midsection and knocking him to the ground.

Continuing his assault, Mario wrapped his hands around Sonic's left ankle and began spinning in place, building up momentum while still keeping his grip on Sonic's leg. After a moment or so of spinning, Mario let go of Sonic, sending the hedgehog flying full force into Mega Man and knocking them both flat.

"It's gonna take a lot more than a little energy blast to keep _me_ down!" Mario declared. Tensing his legs, Mario sprang into the air before coming down, leg extended in a powerful kick. Sonic and Mega Man managed to recover in time to see it coming and roll out of the way before he landed, the ground shaking slightly upon impact.

As the three were facing off, Luigi, Tails, and Rush were also fighting each other. Crouching and tensing his body, Luigi launched himself through the air headfirst in his Green Missile attack, slamming his skull full force into Tails's stomach and knocking the wind out of the fox. Luigi hit the ground rolling with his head tucked in and jumped back to his feet, just in time for Rush to lunge forward and sink his teeth into the green plumber's rump.

Luigi let out a yell of pain and started shaking and twisting his body, trying to get Rush off of him. "That's not a chew toy, you stupid dog!" he yelled. "Let go!"

When Rush's teeth refused to yield, Luigi tried a less subtle approach. He drew back his fist and struck the robot dog across the head once, twice, three times, and Rush fell away. As he rubbed his sore behind, Tails, having recovered, charged in, grabbed Luigi by the straps of his overalls, and flew into the air, taking Luigi with him. After getting to the right height, Tails flung Luigi back to the ground right before Rush, in his jet form, swept in and knocked him out of the sky.

As the three-way fight raged on, however, all six combatants had one thought at the back of their mind:

_If they're working together, why are they all fighting each other?_

* * *

**The Castle, Bowser's Skull Egg Zone **

In the castle, Bowser, Eggman, and Wily's faces were lit with an unholy joy as they watched the battle rage on. They'd even prepared drinks and snacks to watch events pan out, and naturally, everyone cracked up at the sight of Rush biting Luigi's behind.

"Hmm," said Eggman. "So far, they're all evenly matched. This fight could drag on for awhile."

"Aww, who cares?" Wily demanded. "As long as they all kill each other, the fight can rage on until next year, for all I care!"

"True that," Bowser said, before holding out a large tub of popcorn. "Anyone want any?"

As this was going on, the minions let out a loud cheer as Mario jumped on and bounced off of Sonic's head, before suddenly turning and running towards Rose Town, the other five following him.

"What the heck?" Bowser yelled. "What is that faucet freak (3) up to?"

"We'd better find out," said Eggman as he pressed a button on the communicator. "Yoshi Man! Follow them!"

"_Affirmative,_" Yoshi Man replied.

* * *

**Rose Town, Mushroom Kingdom, The Mushroom World  
**

**Mario was panting as he reached the outskirts of Rose Town. As much as he hated to involve the town in this fight, they were starting to wear down. He and Luigi needed an advantage over Sonic and Mega Man, and they definitely knew the streets of Rose Town better than anyone.

No sooner had he and Luigi entered the town has Sonic, Mega Man, Tails, and Rush followed them. As soon as the townsfolk saw what was about to happen, they all began running for cover.

Sonic quickly took the offensive; using his Sonic Boost technique, he charged forward, slammed into Mario, and rammed him into the side of a nearby building. Not stopping there, he let loose with a flurry of punches to Mario's torso, his arms moving so fast that he appeared to suddenly sprout three extra pairs.

Using the distraction to his advantage, Mega Man again aimed his Mega Buster and shot at Sonic, this time using a regular shot. This time, Sonic didn't realize the attack was coming until the bullet hit him in the back. He stopped his assault on Mario and staggered; seizing his chance, Mario sweep-kicked Sonic's legs out from under him before jumping on the hedgehog, grabbing him by the neck with his left hand, and punching him in the face with his right again and again.

"Sonic!" Tails screamed, dashing in and whipping his tails, smacking Mario across the face. Mario recoiled, both hands cupping his big nose before Tails side-kicked him away. Vaulting to his feet, Sonic ran to a nearby building, dashed up the side of it, and then leapt off, tucking into a ball as he did in a Spin Dash. Rolling forward, Sonic bounced from Mega Man, Mario, Luigi, and Rush in that order, striking all four in rapid succession.

Shaking it off, Luigi ran towards Mega Man and tackled the blue robot, who slid back a few inches before planting his feet hard and stopping him cold. Wasting no time, Mega Man kneed Luigi in the gut before clasping both hands together, bringing them over and behind his head, and pounding Luigi's back in a double axe-handle.

Luigi dropped like a load of bricks, stunned by the attack. However, as all the fighters stopped to catch their breath for a minute, they looked around to see something that, in the heat of battle, had missed their notice.

A small crowd of people had started to assemble around them, watching the battle play out. All six of them tensed; if the fight continued as is, there was no guarantee that the Rose Town denizens wouldn't get caught in the crossfire.

"Okay, look," Mega Man said, holding his right shoulder. "I really don't want any of these innocent people to get hurt here, so why don't you two just give up?"

Sonic and Mario looked from Mega Man to one another and back again.

"You don't want any innocents to get hurt, eh?" Mario demanded. "Well, that certainly didn't stop you and Sonic here from trying to kidnap Princess Peach!"

A small chorus of gasps sounded from everyone.

"What are you talking about?!" Sonic yelled. "You and Captain Trigger-Happy here broke into my home on Mobius and kidnapped my mom!"

"I didn't kidnap anyone!" Mega Man objected. "It was you two who broke into Dr. Light's lab and kidnapped my sister Roll!"

A moment of silence followed, before the group began to put two and two together.

* * *

**The Castle, Bowser's Skull Egg Zone  
**

The villains' jaws dropped as they watched the scene play out.

"Crud!" Bowser exclaimed. "They're onto the plan! What are we gonna do now?"

Panicking for a minute, Eggman desperately wracked his brain for a solution before it hit him. He grabbed the communicator and pressed the button. "Yoshi Man!" he began to say. "Destroy-"

"Wait a minute, what are you doing?!" Bowser objected, grabbing Eggman's wrist. "You sic Yoshi Man on them, and they'll only figure out the trap for sure!"

"Would you rather they hash things out and come after us full force, Bowser?" Eggman retorted. "Either Yoshi Man attacks them and takes them out while they're worn down, or that's what will happen!"

"He's got a point, Bowser," Wily agreed. After a moment, Bowser nodded in agreement.

"Very well, then," Eggman said, before turning back to the communicator. "Yoshi Man! Engage and destroy them!"

* * *

**Rose Town, Mushroom Kingdom, The Mushroom World  
**

Before the six could talk it out any further, a small round object came in out of nowhere and bounced in the middle of them. Everyone instinctively recoiled, but Mario and Luigi, after a moment's hesitation, took a closer look. It was a small, white object with green spots. In other words-

"A Yoshi Egg?" Mario wondered. "What in the..."

Suddenly, the egg began to flash red, slowly at first, but faster and faster, with an increasingly fast beeping noise accompanying it.

"Mama-mia, it's a bomb!" Mario yelled. The crowd gasped in horror.

"GET DOWN!" Mega Man screamed. The crowd, along with the heroes, quickly scattered just before the egg-bomb exploded, blasting a crater in the middle of the ground. The six heroes got to their feet carefully, all of them unharmed by the bomb.

***"Where the heck did that come from?!" Sonic shouted, but the others were spared the effort of an answer as Yoshi Man leapt down from a nearby rooftop and landed in front of them. Mario, Luigi, Sonic, and Tails all gasped in recognition.

"Yoshi?!" Mario and Luigi said in unison. "What happened to you?!" Tails gasped.

"Oh, no," he said. "He's been roboticized!"

"Yoshi is no more," Yoshi Man said, his robotic monotone a far cry from Yoshi's peppy, high-spirited voice. "I am now Yoshi Man of the Roboticized Masters."

With that, the shell on his back popped open, and deposited another egg into Yoshi Man's outstretched hand: his Master Weapon, the Eggdozer (4). Winding up, Yoshi Man threw the egg at the group, but they all dove in six different directions, leaving the egg to sail overhead and hit a building right behind a little Toadtot (5) girl.

The bomb exploded on impact, tearing a chunk of debris free which began to fall... right above the Toadtot. Everyone gasped in horror as the little girl let out a high-pitched shriek of terror and braced herself.

"LOOK OUT!" Sonic shouted as he dashed forward in a blur, scooping the Toadtot up in his arms and zipping out of the way a split second before both would have been crushed by the falling debris. As soon as they were out of harm's way, a middle aged female Toad, obviously the child's mother, came running up to Sonic, who unhesitatingly handed the girl over.

"Mommy!" the Toadtot squealed, wrapping her little arms tightly around her mother's neck.

"Thank goodness you're okay!" her mother sobbed happily, turning to Sonic. "Bless you, sir. Bless you!"

"No need to thank me," Sonic said hurriedly. "Just get to safety now!"

The Toad nodded and dashed off, her child in her arms, while Sonic turned back to Mario and Mega Man.

"Okay, I'm still not sure what's happening, but what do you say we call a truce at least until we stop Yoshi Man?" he said.

"Agreed," said Mega Man. "Putting little kids in danger is _not_ okay." Mario, Luigi, and the others nodded in agreement, before Mario turned to Yoshi Man.

"Yoshi, please," he said. "I know you're in there somewhere. You've gotta fight it. I don't wanna hurt you, but I will if I have to."

For a brief moment, Yoshi Man actually shook visibly, and his eyes flickered before they became ice again.

"I already told you, plumber," he said. "Yoshi is gone."

With that, he drew back and slammed both of his open palms into Mario's chest full force, sending Mario flying backwards, totally airborne. The plumber slammed back-first into a building, and hit the ground, letting out a grunt in pain. Luigi quickly ran over and carefully helped his older brother up.

"Bro, what are we gonna do?" he asked as the others crowded around them.

"I've got an idea," Mega Man said. "A Charge Shot from my Mega Buster might be enough to take him down without killing him, and then maybe we can figure out what to do from there. But you guys gotta distract him long enough for me to do it."

"You got it," Mario said. "Let's-a go!"

"Okey-dokey!" Luigi agreed, and with that, Mario, Luigi, Sonic, and Tails all jumped into the fray. Before they reached him, Yoshi Man opened his mouth, and a long, metal pink tongue snapped out, wrapping around Mario's right ankle before bodily lifting him off the ground and slamming him against the ground. After a few slams, Yoshi Man jerked his head to the side and slammed Mario into Luigi, knocking them both sprawling.

While Yoshi Man was focused on the Mario Bros., Sonic dashed in at full speed, running in circles around him at a blur. Soon enough, Sonic's sheer speed whipped up a tornado which caused Yoshi Man to levitate off of the ground. As soon as Yoshi Man was about a foot off of the ground, Sonic cut off the wind, jumped into the air, and used a Homing Attack to slam Yoshi Man back to the ground.

At that moment, Mario and Luigi got back to their feet. Nodding to one another, they both jumped into the air at the same time. Somersaulting in mid-jump, the two let out dual yells as they stomped down on Yoshi Man full force.

"Okay!" Mega Man yelled, his body glowing with a blue light. "The Charge Shot's ready! Everyone get back!"

The four heroes all jumped out of the way as Mega Man fired the shot. Just as Yoshi Man was getting back to his feet, the Charge Shot slammed into him. As soon as the energy faded, Yoshi Man simply stood there, sparking with electricity, frozen in place. Mega Man looked on curiously.

"Why does this look familiar?" he said to himself as he made his way over to the immobilized Yoshi Man. Carefully, he placed his hand on Yoshi Man's chest, and suddenly, both he and Yoshi Man were enveloped in light.

"What's happening?!" Tails shouted as they looked on. Rush let out a whimper, scared for his master.

The light faded as quickly as it appeared, and when they could see clearly, they looked on in awe.

Mega Man's coloration had changed. Instead of being cyan with a blue helmet, forearms, boots, and briefs, he was now white with a green helmet, forearms, boots, and briefs; the same color as a Yoshi Egg. And in place of Yoshi Man, there was an unconscious, yet flesh-and-blood Yoshi laying at Mega Man's feet.

"Yoshi!" Mario yelled, running over and kneeling at his friend's feet. Much to his relief, Yoshi was still breathing.

"How did you do that?" Sonic asked as the others crowded around. Mega Man looked at him in confusion.

"I... I don't know," he admitted. "I was just trying to copy his Master Weapon data, and this happened."

"Master Weapon?" Tails said. "You mean those egg bombs?"

"Time out for a second!" Luigi exclaimed, making a "time-out" sign with his hands. "What in the name of the Mushroom Kingdom is going on here?!"

"First things first," Mega Man said, shifting back to his normal color. He gently picked Yoshi up and slung the green dinosaur over his shoulders in a fireman's carry. "We need to get Yoshi here some help."

Mario nodded. "You guys follow me and Luigi back to Toad Town. We can figure things out from there."

* * *

**Author's Note:  
**

(1): Taken from the final fight scene of _Tekken: Blood Vengeance._

(2): In the first mission of Dinosaur Jungle from _Sonic and the Secret Rings,_ Sonic mentions his quills are tingling before a T-Rex attacks him.

(3): "Faucet freak" was one of the various insults Bowser gave Mario and Luigi in _The Super Mario Bros. Super Show!._

(4): Eggdozer, taken from the Mega Eggdozers of _Yoshi's New Island._

(5): "Toadtot" is, of course, the name for a kid Toad. I got the term from TimeLordParadox's story _Mario and Luigi: The Mask. _

Well, Yoshi's been cured, and our heroes have figured out they've been set up. What's gonna happen next? Stay tuned to find out!


	7. Heroes United

**- Chapter 6 -**

**Heroes United  
**

* * *

**The Castle, Bowser's Skull Egg Zone **

Meanwhile, back in the BSE Zone, Bowser, Eggman, and Wily were not pleased at all. The screen had gone black after Mega Man copied Yoshi Man's Master Weapon into himself, and they could only assume what had happened.

"Dang it all!" Bowser raged, a tongue of flame escaping from his mouth. "They beat Yoshi Man! Now they'll be on to us for sure!"

"Calm down, Bowser," Wily said, both hands raised in a "take it easy" gesture. "They still don't have a clue about the existence of the BSE Zone, so time is on our side for now." Bowser took a few deep breaths, and composed himself.

"You're right, Albert," he said. "Even so, we may need a little extra help. I'm not the only bad guy from my world, and I doubt you two are either."

"So, you're saying we should try to team up with the other bad guys?" Eggman said. "How are you even sure they'll go along with it?" Bowser thought for a minute.

"Well, that's a bridge we'll have to cross when we get to it." he said.

The doctors both face-palmed at that.

"In any event," said Eggman, "we've still got the other Roboticized Masters as collateral."

The trio looked over to a group of figures concealed in shadow.

* * *

**Peach's Castle, Toad Town, Mushroom Kingdom, The Mushroom World  
**

Inside the master bedroom of Peach's Castle, a small group had assembled.

Mario and Peach were sitting anxiously on the edge of Peach's bed, where under the covers was an unconscious Yoshi. Luigi was pacing around nervously, his hands behind his back, while Sonic and Tails stood off to the side, leaning against the wall in thought. Mega Man was sitting at the foot of the bed, stroking the top of Rush's head.

It had been about an hour since the sextet's showdown with one another, and then Yoshi Man, in Rose Town. Naturally, when Sonic and Mega Man had arrived in Toad Town after the two had supposedly tried to kidnap Peach, there was a brief moment of fear among the denizens, but Mario and Luigi had managed to explain the situation and calm everyone down before bringing Yoshi to Peach's Castle. Now the group was just waiting for him to wake up so they could get some answers.

At that moment, they heard a knocking at the door. "Come in!" Peach called.

The door opened, and in came two Toads, one male, one female. It was Toad, one of Peach's loyal retainers, and his twin sister Toadette (1).

Toad wore a white mushroom cap with red spots, a blue vest with gold trim, and diaper-like white bottoms with brown shoes. Like most Toads, he was short and somewhat childlike, with no apparent legs or nose and beady black eyes.

Toadette looked much the same, though her mushroom cap was pink with white spots, with a matching pair of pink plaits. She wore a pink dress with a thin white line near the bottom under a red vest with gold trim, with the trademark white bottoms and brown shoes.

"How is he, you guys?" Toad asked, making his way over to the bed.

"He's got a few scratches and bruises, but mostly, he's just exhausted," Mega Man answered.

At that moment, they heard a rustling, and all heads turned to see Yoshi beginning to stir. His eyelids fluttered, then slowly opened, to see Mario looking at him with relief.

"He's awake!" Mario shouted. Almost immediately, Mega Man, Rush, Sonic, and Tails scrambled over to the bed.

"M-Mario?" Yoshi said, sitting up slowly.

"I'm here, Yoshi," Mario said. "Are you okay? Does anything hurt?" Yoshi shook his head.

"No, I'm fine," Yoshi said. "Just tired." Mario let out a relieved sigh.

"Okay, I think I know the answer to this already, but I've got to make sure," Mario said. He jerked his thumb at Sonic and Mega Man. "Are these two the ones who captured and did that to you?"

Again, Yoshi shook his head. "No, it wasn't them," he said.

"Then who?" Sonic asked. Yoshi closed his eyes for a minute, but then they snapped wide open.

"I... I remember now," he said. "I was still on Yoshi's Island when it happened..."

* * *

**Flashback  
**

**Yoshi Village, Yoshi's Island, Dinosaur Land, The Mushroom World**

The sun was shining bright as Yoshi prepared to exit his home in the Yoshi village. The village was actually rather modern for Dinosaur Land. Unlike the dome-shaped buildings of their neighbor Dome City (2), the houses were made of strong, stone bricks, with roofs made of thick wooden sticks that were tied together, whereas the outsides of the houses were painted bright colors to match the mood of the Yoshi civilization. The Yoshis were walking around everywhere, having conversations, and playing games with each other. It was just another ordinary day.

However, the day would soon prove to be not-so-ordinary, as when Yoshi opened the door, he encountered three figures. The first two, a Magikoopa wearing a blue robe and cone hat with black-rimmed circular glasses and a short, egg-shaped robot colored red, yellow, and black with blue eyes and mouth, black three-fingered hands, and a pointy nose, he easily recognized as Bowser's minion Kamek and one of the Egg Pawns they competed against in the Real World Olympic Games. It was the third figure, a tall man wearing a white jumpsuit with black-and-yellow shoulders, chest, forearms, and calves, white feet and hands, a black helmet with a yellow cobra-like hood and blue cross-shaped marking, red eyes, purple stripes on his cheeks, and a triangular blue crystal on his chest, whom Yoshi didn't recognize.

Yoshi took a step back, ready for a fight. "What are you doing here?" he demanded.

"That's not important, lizard boy," the black-armored man said impatiently. "Our bosses need you for something."

Before Yoshi could react, the man jumped forward and punched him in the face, and everything went black.

* * *

**The Castle, Bowser's Skull Egg Zone**

When Yoshi came to, he found himself enclosed in a glass capsule in the middle of a dark room. He rammed his shoulder into the capsule, but it didn't budge an inch.

"Don't bother struggling," a voice cut in, a voice Yoshi recognized as Dr. Eggman's. "That capsule is made of Plexiglas. There's no escape."

Yoshi searched for the source of the voice, but couldn't see anything. "What's going on?" he yelled.

"We need your services for a while, Yoshi." another voice cut in, which Yoshi also recognized as Bowser.

"As if! I'll never work for you! Never!" he said defiantly.

A third voice, one Yoshi didn't recognize, laughed at that. "Funny," it said. "You must have us confused with someone who was giving you a choice. Now, prepare to be transformed!"

Before Yoshi could ask what they meant by that, he heard a loud whirring noise, like a jet turbine powering up, and then saw a large, spherical device come down out of the ceiling, glowing with a pink light. He didn't know what was about to happen, and he didn't want to. Frantically, he pounded on the glass, desperate to escape.

"Noooo!" Yoshi yelled. "Stop! _Stop!_"

But there was no stopping it. The sphere shot a pink laser onto the capsule, bathing Yoshi in a pink light. He felt a strange itching sensation, and looked at his arm. To his horror, his green flesh was turning into metal, and it was spreading to the rest of his body!

Yoshi let out a scream of pure horror which was cut off abruptly as the process completed, leaving a robotic version of himself in his place.

"From now on," the three voices said in unison, "you serve us... Yoshi Man."

Yoshi was aware of what was going on, he could see and hear everything, but he had no control over his body. Some other mind, other personality, was in control, and it was this second robotic personality that responded, "Yes, Masters."

**Flashback Over**

* * *

**Peach's Castle, Toad Town, Mushroom Kingdom, The Mushroom World  
**

As Yoshi finished his story, everyone looked at him, expressions of mixed shock, rage, and horror on their faces.

"Those monsters!" Peach cried out. "How could they possibly do that to you?!"

"I know," Tails said. "Even for Bowser and Eggman, that's low!"

Mega Man said nothing, his eyes closed and a thoughtful expression on his face. "That boy in black armor you mentioned," he said finally. "I know him. His name is Bass."

"Bass?" Mario asked. Mega Man nodded.

"Yeah. He was created by a villain from my world, Dr. Wily."

Everyone gasped. The pieces were finally coming together.

"So, our respective arch-rivals somehow met each other, and they've teamed up to take us all out!" Sonic said. "They set us up to think we kidnapped Roll and my mom so we'd kill each other, and when we figured it out, they sicced Yoshi on us!"

Mega Man nodded. "We definitely got off on the wrong foot here," he said, holding out a hand. "My name's Rock Light, or Mega Man, whichever you prefer. And this," he said, scratching Rush behind the ears, "is Rush. I hope we didn't hurt you guys too bad."

Mario took Mega Man's hand and shook it. "I'm Mario, and this is my brother Luigi," he said. "And don't worry, no harm done."

As soon as Mario finished the handshake, Sonic shook Mega Man's hand himself. "I'm Sonic," he said. "Sonic the Hedgehog."

"My name's Miles Prower, but everybody calls me Tails," said Tails.

"I am Princess Peach of the Mushroom Kingdom," said Peach. "These are my loyal retainers, Toad and Toadette."

"Nice to meet you," Mega Man said. "Now that I think about it, I can't believe I was tricked by that fake Mario and Sonic. Sure, they look like you two, but they're anything but perfect copies."

"Same with me and that Shadow Mario guy," Sonic said, embarrassment evident in his voice. "That fake you, though, was a perfect copy. Except for the scarf, of course."

"Now that that's out of the way," Tails said, "how are we gonna stop Bowser, Eggman, and Wily and get Sonic's mom and Rock's sister back?" Luigi thought for a minute, then smiled.

"I think I know a certain mad scientist who can help us."

* * *

**Author's Note:  
**

(1): Since Nintendo doesn't really specify Toad and Toadette's exact relationship, I've decided to make them twins here.

(2): Dome City was the city of cavemen from the _Super Mario World_ cartoon.

Another chapter down. Please R&R.


	8. A Meeting with E Gadd

**- Chapter 7 -**

**A Meeting with E. Gadd  
**

* * *

**The Castle, Bowser's Skull Egg Zone **

Eggman and Wily sat in their respective chairs, waiting patiently for Bowser to return with the first of his supposed allies. He had left some time ago, but did not really specify how long it would take for him to return.

As it turned out, they didn't have to wait long. A portal opened up in front of them, and through it came Bowser, accompanied by his ally, who was a spherical white ghost with black eyes, four fangs, stubby arms, a golden five-pointed crown encrusted with one red jewel and four blue ones. It was none other than King Boo, ruler of the Boos.

"Ah, King Boo," Eggman said, nodding in his direction. "Another familiar face from the Olympics (1)."

"Okay, wait," said Wily. "So does _everyone_ from the Mushroom World and Mobius know each other from the Olympic Games? Why would you even play sports games and whatnot with Mario and Sonic? You're supposed to be enemies!"

"Just because we're enemies doesn't mean we can't call truces and have some fun once in a while, Wily," Bowser shot back.

"Enough chitchat," King Boo said sharply. "What exactly did you bring me here for, Bowser?"

"It's simple, really," Bowser replied. "I couldn't help but learn about your recent defeat in Evershade Valley at the hands of Green 'Stache."

As soon as the worlds "Green 'Stache" left Bowser's mouth, King Boo's eyes changed from black to glowing red, his face contorted in rage. Eggman and Wily immediately recoiled in fear and ducked behind their chairs.

"Luigi?!" King Boo snarled. "Curse him! Curse him to the Underwhere! If I ever see his ugly mustached face again, I'll-"

"Cool it, Boo!" Bowser shouted. King Boo composed himself with an effort, his eyes dimming down. "This is why we brought you here. The three of us are working together to take down our respective foes, Luigi included, but they've already taken down one of our top minions. How would you like another shot at revenge on him?"

King Boo didn't have to think it over for more than one-eighteenth of a second. He grinned and let out a devilish cackle.

"I'm in," he said. "What's our next step?" Bowser sneered.

"Knowing Mario, I'll bet a million coins that he'll be paying a visit to Professor E. Gadd right about now."

"E. Gadd, hmm?" King Boo grinned. "Perfect! I can kill two birds with one stone!"

"And for an extra bonus," said Eggman, "we'll be sending our new Roboticized Master with you."

As if on cue, a big burly robot stepped forward, ready to fight...

* * *

**Boo Woods, Mushroom World, The Mushroom World  
**

Mario, Luigi, Yoshi, Sonic, Tails, Mega Man, and Rush were all standing at the entrance to the Boo Woods. The trees were creepy-looking, with no sign of any leaves on them. A small river, which was nearly dry, flowed through the woods into a swamp located in the middle of said woods. Not too far from the group was a large hill, over which was their destination: the laboratory of Professor Elvin Gadd, one of the top scientists of the Mushroom World, and paranormal researcher extraordinaire.

"Boy, this place sure is creepy," Mega Man said nervously. Rush woofed in agreement.

Sonic scoffed. "Please," he said. "I ain't afraid of no ghosts (2)."

Luigi let out a nervous, audible gulp. He thought he had finally conquered his fear of ghosts, but apparently, it wasn't as thorough as he thought it was. Mario turned to his brother and put a comforting arm around him.

"C'mon, Luigi, you can do this," he said. "It's broad daylight out, and we all know that the Boos are scared of the light." Luigi took a deep breath and nodded.

"Okay, let's go," he said. Before they could enter, however, a voice reached their ears.

"Wait! Hold up a second!"

The seven turned to see a small brown-furred monkey wearing a red shirt with yellow stars on it, a red baseball cap with a white Nintendo logo, and a beige backpack running towards them. It was Diddy Kong.

"Diddy?" Mario, Luigi, Sonic, and Tails all said in unison (3).

"What are you doing here?" Yoshi asked as Diddy reached them. Diddy panted for a minute, trying to catch his breath.

"It's DK!" he exclaimed. "He's gone missing!"

"Missing?!" the others exclaimed. "Are you sure?" Diddy nodded.

"Yeah. He went out a few hours ago to get some bananas and never came back," he explained. "I came here from Donkey Kong Island to see if anyone had seen him, and Princess Peach sent me your way."

"Well, I'm sorry, Diddy, but we haven't seen DK." Sonic said. At that moment, Mega Man snapped his fingers.

"Hold on a minute!" he said. "Did you see anyone suspicious around your island before DK disappeared? Anyone or anything out of the ordinary?"

Diddy took off his cap to scratch his head for a moment in thought. "Now that you mention it, I think I did see that Kamek goon who works for Bowser flying around somewhere, but I didn't really pay much attention. Why?"

Everyone else's eyes widened. It was obvious what had happened.

"We'll explain on the way," Tails said. "We're paying Professor E. Gadd a visit, Diddy. Why don't you tag along?"

Diddy nodded. "Okay, might as well."

With that, the group entered the woods. It was extremely quiet, and actually quite peaceful for an area supposedly filled with ghosts. As they walked, they took the opportunity to bring Diddy up to speed on what was happening.

"So, you think that Bowser, Eggman, and this Wily person kidnapped DK and turned him into one of these Roboticized Masters like he did with Yoshi?" Diddy asked, mortified at the thought of his best pal being a robot slave. "That's terrible."

"I pray that I'm wrong, Diddy, but it does fit together." Mega Man said.

"If it did happen, don't worry," Mario said reassuringly. "We'll get him back."

At that moment, Rush stepped on a twig, which caught Luigi off-guard. He let out a loud scream of terror and jumped about a foot in the air, shocking everyone else.

"For Pete's sake, Luigi!" Sonic said, trying to smooth his quills, which were standing on end. "Can you give us a little warning next time?"

Luigi just stood there, shaking like a leaf and muttering to himself.

"Enough, Luigi!" Mario said, annoyed, as he grabbed Luigi by the collar and slapped him across the face. "Get a hold of yourself!"

Obediently, Luigi hugged himself, still trembling. "Okay, but it's not helping much." Mario pinched the bridge of his nose in annoyance.

"What are we gonna do with you?" he said, more to himself than anyone else as the group continued on their way.

Before long, they reached E. Gadd's lab, a small, metal dome that looked to be in the shape of someone's head, complete with windows shaped like glasses and a door shaped like a mouth.

"I'll never understand people's tastes in this world," Sonic said, looking at the bizarre building.

Luigi walked up to the door and rang the bell. Unexpectedly, the door swung open on its own.

"Well, that's ominous," Mega Man said. Nonetheless, the group made their way inside, finding themselves in what appeared to be a small living room. On the far wall sat a well-worn, but still usable couch with a coffee table in front, and on the opposite wall sat a large TV set, with a record player that was on and playing a somewhat ominous, but catchy tune (4).

"Well, where is he?" Sonic asked, putting his hands on his hips.

As if in response, the middle of the ceiling suddenly opened up. The gang gave the opening a wide berth as an elevator descended and opened up, revealing a small old man, human like Mario and Luigi, but shorter. He has a single horn-shaped tuft of white hair in the middle of his head, black-rimmed glasses with spirals on the lenses, a white lab coat with a red dress shirt underneath, along with black pants and brown shoes.

"Professor Gadd!" Mario and Luigi said together, recognizing him. The Professor smiled.

"Ah, the Mario Bros.!" he said. "Nice to see you again!" He looked at Yoshi, Diddy, Sonic, and Tails. "Ah, Sonic and Tails! I've heard about you and your friends from the Olympic Games in the Real World. I'm sorry I missed those." Finally, he turned to Mega Man and Rush. "Haven't seen you before, young feller. And you are?"

Mega Man stepped forward. "I'm Rock. Rock Light, but most people call me Mega Man," he said, then scratched Rush behind the ears. "And this is Rush."

"Pleased to meet you both," Professor Gadd said. "So what brings you youngsters all the way out here to the Boo Woods?"

"It's a long story, Professor," Mario said. "You might want to sit down."

E. Gadd did just that, and the group spent the next several minutes outlining the situation with Bowser, Eggman, and Wily, and what exactly they came for. Mario and Luigi had the idea that the Professor could build some form of device that would enable them to link the Mushroom World to Mobius and Earth 20XX and perhaps get help from Sonic's and Mega Man's respective allies, maybe even find out where the villains had taken Roll and Bernie.

E. Gadd stood there for a moment or two, scratching his chin in thought, and then snapped his fingers. "Aha!" he said. "I might have something that we could use."

With that, he stepped back into the elevator, motioning for the others to follow. It was a tight fit for all nine of them, but they managed it. The elevator door closed, and ascended back up the shaft from where it came. After a few moments, it stopped, and the group piled out into none other than E. Gadd's laboratory, filled with various deactivated gadgets and inventions. Tails, ever the fascinated inventor, was particularly impressed.

"There'll be time to admire things later, Tails," E. Gadd said. "Follow me."

Tails let out a little moan in disappointment. With that, E. Gadd led them to a large yellow-painted machine with a clock on the front, with two bell-like objects on top with a lightbulb in between them. Mario and Luigi recognized it: E. Gadd's old Time Machine.

"Your Time Machine?" Mario said. "Professor, we need to travel through dimensions, not time."

E. Gadd chuckled. "Mario, my boy, I was just getting to that," he said. "With a few modifications here and there, we can give this machine just that capability."

"No kidding!" Mega Man said, amazed, and so was everyone else.

E. Gadd nodded. "Yep. But we're gonna need some power to make it work."

"How are we gonna get enough power?" Tails asked.

E. Gadd started walking again, motioning for the rest of the group to follow. They went through a door on the left side of a room to E. Gadd's workshop, complete with a desk, various blueprints, a bookshelf, and a computer that took up much of the wall on the opposite side of the door. What really caught the group's attention, however, was a rotating yellow star with beady black eyes in a glass container on the desk. Mario, Luigi, and Yoshi recognized it instantly.

"A Power Star!" they exclaimed. E. Gadd nodded.

"That's right," he said. "I found it the other day, figured I could use it to power one of my inventions. But just one isn't enough."

"So, we're gonna need to find a bunch, huh?" Diddy asked. "That could take a while." E. Gadd held up his hand at that.

"Don't worry, fellers, I thought of that. I studied this Power Star's energy signature and used it to whip up a new gadget just in case something like this happened."

With that, he opened the top drawer of the desk and withdrew what appeared to be a Game Boy Color. Luigi recognized it immediately.

"Your Game Boy Horror?" he said, remembering he had used the device while going through King Boo's haunted mansion some time ago.

"That's right," E. Gadd said. "I updated it with a new feature that lets it detect the Power Stars and similar objects of great power. Just press the Start button..."

As he said this, E. Gadd pressed the Start button, and the screen shifted to a radar screen, with a star-shaped blip flashing off to the side.

"...and this little radar pops up and shows you where they are."

"Cool!" Sonic exclaimed. "This'll make finding them a snap!"

"I'll get started on the adjustments right away," E. Gadd said. "You guys can-"

But at that moment, a loud crash sounded that shook the entire building.

"What the heck was that?!" Mega Man said.

"It came from outside," Mario said. "Professor, you stay here. We'll check it out!"

E. Gadd nodded, and the group descended the elevator and exited the lab to see a face Mario and Luigi hoped they wouldn't see again.

"King Boo!" they shouted. Everyone instantly tensed.

"That's right," King Boo declared. "Bowser, Eggman, and that Wily guy talked me into helping them out, and I'm here to take you down."

"You're working with the Three Stooges too?" Sonic asked. "Jeez, what is this, some kind of supervillain jamboree?"

"Pretty much," King Boo said, smirking. "The best part is, I'm not alone!"

At that, a large figure jumped down in front of them. It was a large, robotic gorilla with a chocolate brown paint job, pale white hands, feet, abs, stomach, and muzzle, and emotionless red eyes, the look completed by a red stripe descending from his neck to his belly with the letters "DK" printed in yellow on the front. Mario, Luigi, Sonic, Yoshi, Tails, and Diddy had no trouble recognizing the figure despite his changed appearance.

"Oh, no," Diddy said, in shock. "No, no, no..."

"It can't be," Mario said, also shocked. "Not you too, DK."

It was just as they feared. Like Yoshi before him, Donkey Kong had been captured by the villains and converted into a Roboticized Master.

* * *

**Author's Note: **

(1): King Boo appeared in the first, third, and fourth Mario and Sonic Olympics games as a rival.

(2): Heh, _Ghostbusters_ reference.

(3): Yes, I know Diddy hasn't appeared in any of the Olympics games yet, but for the sake of the plot, and since there is AU in this story, let's say he did here.

(4): The tune in question is the record player theme from _Luigi's Mansion: Dark Moon._ It can be found at this link: www. youtube watch?v=F5eGi4JGWJc

Oh, noes! Donkey Kong's a Roboticized Master! What are they gonna do now?!

Find out next chapter! Please R&R, my peeps!


	9. Kong Clash

**- Chapter 8 -**

**Kong Clash  
**

* * *

**Author's Note: **

Just FYI, I changed the story's category from a Mario and Sonic crossover to _Super Smash Bros._ because I felt, since Mario, Sonic, and Mega Man are all in _Smash Bros._, it'd be a better way to cover it. However, only characters from Mario, Sonic, Mega Man, and their respective spin-offs are going to appear in this story, so don't expect any real appearances from Link or Samus or whatever, okay? Maybe in my next story.

And to answer my reviewer werewolf99, King Boo's line "Curse him to the Underwhere!" was just that. According to _Super Paper Mario_, the afterlife in Mario's world is called the Underwhere.

I would also like to thank my reviewer blee7442 for informing me of an error I made in the last chapter with King Boo's appearances in the Mario & Sonic games; he didn't appear in the first game, but he _did_ appear in the second one onwards. I misread the article I got it from. Derp.

Okay, and now for the music in this chapter:

* _Kingdom Hearts Re:Chain of Memories_- The Fight for My Friends: https: www. youtube. com watch?v=a_FfJIn4mTw

* * *

**E. Gadd's Lab, Boo Woods, The Mushroom World  
**

Mario and the others stood before King Boo and the roboticized Donkey Kong, ready to fight, but reluctant. Without warning, Diddy walked forward, his hands outstretched.

"DK, come on, big buddy!" he pleaded. "It's me, Diddy! Don't you recognize me?!"

King Boo let out a cackling laugh. "Donkey Kong is gone, you stupid little chimp!" he declared. "There is only DK Man now!"

Mario turned to Mega Man. "Do all Robot Masters from your world have the word 'Man' in their names?" he asked.

"Yeah, more or less," Mega Man replied.

"Enough talk," King Boo spat. "It's time for my revenge. DK Man, _ATTACK_!"

*"Affirmative," DK Man said, his voice a robotic baritone. He pulled back his balled right fist, and his right elbow suddenly opened up and sprouted a jackhammer-like piston; DK Man's Master Weapon, the Kong Quake (1).

"I'LL CRUSH YOU! (2)" he bellowed. With that, he sprang into the air and slammed his fist into the ground when he landed, creating a sizable shockwave that the group had to jump to avoid.

"This isn't good," Mario said. "I don't wanna fight DK, but we have no choice."

"Ugh, what the heck are we gonna do?!" Sonic demanded.

"I've got it!" Mega Man declared. Everyone looked at him. "Remember when we fought Yoshi Man, and our combined attacks somehow changed him back to normal?"

The others nodded.

"Well, what if we tried that again?" Mega Man suggested. "Mario or Sonic could hit him with a Super Jump or Spin Dash, and I could hit him with a Charged Shot, and that could change Donkey Kong back!"

"Good plan," Sonic said. "But I've got a better idea. Tails, are you thinking what I'm thinking?"

"I think so," Tails said. "I can modify Rock's Mega Buster so that his Charge Shots can give off the same energy signature as your Spin Attacks, and then he can change DK back by himself."

"We'll call it the Sonic Shot!" Sonic said. Both he and Mega Man hesitated for a moment.

"Why does that sound familiar?" they both said aloud before shaking their heads.

"Are you goofballs done jabbering so we can get on with the death and destruction?" King Boo snapped impatiently. "I've got places to destroy and people to kill here!"

"Yeah, we're ready," Luigi said. "Ready to kick your spooky butt!"

"Tails, we'll keep him busy," Sonic said. "You do your stuff."

"You got it!" Tails said. "Rock, let me see your Buster."

Mega Man obediently converted his arm into the Mega Buster, and Tails pulled out a screwdriver and popped open a panel on it, promptly starting to tinker with it.

As this was going on, Mario brandished his hammer. He knew this fight wasn't going to be easy. Donkey Kong was always incredibly strong even for a gorilla, and as a robot, he was most likely even more powerful than before.

Diddy slowly drew his Peanut Popguns. As much as he hated to fight his best friend, he knew they had no choice. With that, he aimed at DK Man and fired off a quick burst of peanuts. The force of the projectiles managed to stagger DK Man briefly, but that was about it.

Sonic quickly dashed in and delivered a bicycle kick to DK Man's head. As DK Man reeled back, Sonic threw a punch, only for DK Man to effortlessly catch his fist and stop him cold.

"Nice try, blue boy," DK Man said, sounding almost bored, before flinging Sonic into the air and catching him in both hands on the way down, holding the blue hedgehog before him like a doll.

"Excellent!" King Boo shouted, dancing in the air like a madman. "Crush his bones!"

At that order, DK Man began to squeeze Sonic between his hands. Soon, he was crushing the hedgehog, tightening his grip slowly but steadily; the pressure on his body was so much that Sonic thought his head was going to explode!

But just as Sonic was beginning to pass out, something flew through the air and slammed into the side of DK Man's head with a loud metallic _clang_. As soon as it made impact, DK Man stumbled back, releasing his crushing grip on Sonic and dropping him to the ground.

As he got his bearings, Sonic saw the object that hit DK Man: Mario's hammer. Mario collected the hammer, which he had thrown at DK Man to get him to let go of Sonic, and made his way over to Sonic.

"Are you okay?" he asked, offering his hand. Sonic took the hand and allowed Mario to help him up carefully before feeling his arms and legs; he was bruised up pretty good, but fortunately nothing seemed to be broken.

"I'm kinda sore, but I've had worse." he replied.

"You stinking _PLUMBER!_" King Boo howled. "Get him!"

Before Mario and Sonic could react, DK Man darted in with incredible speed, his fist crashing into Sonic's back with the force of a pile driver and sending him sailing into the side of E. Gadd's lab. As soon as Sonic was out of the way, DK Man snatched Mario up by the overalls and slammed him into the ground, converting his free arm back into the jackhammer.

"Game over for you, Stupid Mario!" King Boo snarled, utterly demented. "Mash him! Stomp him! Crush him!"

With that, DK Man slammed his jackhammer arm on top of Mario, his fist retracting and shooting downward to match the motions of the piston in his elbow, and pummeling Mario into the ground. Before long, a small crater had formed on the spot, but DK Man was clearly not going to let up until Mario was crushed into a pulpy pancake.

"Mario!" Luigi screamed, jumping into the air and landing right on DK Man's head, getting him to stop his assault. Mario shakily got to his feet, dazed.

"Anybody get the number on that Wiggler Bus?" he said. Sonic also got to his feet as well.

"C'mon, Tails!" he shouted. "How much longer?!"

"Just a few more seconds!" Tails replied, pressing a few buttons on Mega Man's buster. Finally, he slapped the panel closed, and the buster flashed a bright blue for a moment.

"Okay, Rock, let 'er rip!" he said. Mega Man promptly took aim, charged up the necessary energy, and fired, a ball of surging energy that looked precisely like Sonic in Spin Dash form blasting out and hitting DK Man head-on.

"_No!_" King Boo howled as DK Man was surrounded in a ball of light. When it faded, in DK Man's place was a living gorilla with chocolate brown fur, flesh-colored hands, feet, abs, stomach, and muscle, and a red necktie with the letters "DK" printed on it in yellow.

"DK, you're back!" Diddy declared happily, jumping at Donkey Kong and giving him a hug. DK gave his pal a smile, then turned to King Boo in anger.

"You and your buddies thought you could just use me like that and get away with it?!" he said angrily. "Well, _think again_!"

With that, he brought his hands together in a massive clap that produced a powerful shock wave, which blasted King Boo into the sky with a loud scream.

"Good to have you back, Donkey Kong," Mario said, patting his friend on the shoulder. DK nodded.

"Alright, I don't know what Bowser and Eggman are planning," he said, "but they're not gonna get away with this." It was at that moment that the group noticed a small, brown sphere of light floating nearby. Mega Man, acting without thought, grabbed the sphere in his hand, and it was promptly absorbed into his body.

After a moment, Mega Man's color scheme changed to match DK Man's, the blue parts turning dark brown and the cyan parts turning a fleshy color, with a stripe of red extending from his neck to his midsection. He proceeded to convert his arm into a piston.

"I've got DK's Master Weapon now," Mega Man said as he shifted back to normal. Mario nodded, and withdrew the Game Boy Horror from his pocket.

"Well, let's get started. There's a long road ahead."

* * *

**The Castle, Bowser's Skull Egg Zone  
**

Deep within the castle's laboratory, Eggman was putting the finishing touches on his latest robot, a tall, egg-shaped robot with a red, grey, and black color scheme, long metal pincers for hands, and dull cyan eyes. He pressed a few buttons, and the robot's eyes lit up.

At that moment, the door slid open, and Bowser and Wily entered the room.

"We've got bad news, Ivo," Wily said. "The heroes have defeated DK Man."

"What?!" Eggman shouted. "That's two Roboticized Masters down already!"

"Relax, it's not the end of the world," Bowser said, surprisingly calm. "We've still got the others, and our plans are still going strong. Now then, what's this thing here?"

Eggman grinned. "My newest masterpiece. Yoshi Man and DK Man may have fallen to those do-gooders, but they _will_ fall to Burnbot!" The robot rose to its full height at the mention of its name.

"Burnbot?" Wily said. "So, he's gonna burn them to death with flamethrowers or something?"

Eggman raised an eyebrow in confusion. "Flamethrowers? Well, no-"

"How about acid?" Bowser asked.

"Incendiary grenades?" Wily remarked.

"No, you fools!" Eggman snapped impatiently. "Claws! His claws! Very painful claws!" As if on cue, Burnbot raised its arms and snapped its pincers together. Bowser and Wily looked at him like he had just grown three heads and a tail.

"Let me get this straight," Bowser said. "You named a robot that fights with claws 'Burnbot'?" Eggman nodded.

"Kind of a ridiculous name, really." Wily said, right before Eggman got to his face.

"It's _my_ robot, Albert!" he snarled. "_I_ built it! _I _can name it whatever I want!"

"Cool it!" Bowser shouted. "I don't care if you named the robot Lizzy as long as it takes Mario and his goody-two-shoes friends down!" Eggman grinned evilly.

"Oh, don't worry, Bowser. I'll bet my mustache that Burnbot will be their toughest fight yet."

* * *

**Author's Note:  
**

(1): Based on DK's Hand Slap attack, as well as Armodrillo from _Ben 10_.

(2): A quote taken from Garland in _Dissidia: Final Fantasy._

The scene with Burnbot was taken largely from the first TV trailer for _Sonic Boom_.

I apologize for the long wait, but I've been working on my other stories and had writer's block. And have no fear, Sonic, Mega Man, and their associated characters will remember the events of _Worlds Collide_ soon.

Please R&R. Until next time...


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